1. Field of the Invention
The present invention relates generally to mechanisms for activating electrical switches. More specifically, the present invention concerns a button assembly with an integrated light pipe for use with a shuttle knob mechanism.
2. Description of the Background Art
Assemblies for selectively actuating switch closures in response to a manual movement of a member, such as a button assembly, have seen increasing utility and are often found in devices such as computer interfaces, joysticks, automotive mirror controls and the like. Illuminated button assemblies, and applications in, for example, telecommunication devices, televisions and associated peripherals (i.e., control boxes, remotes, video players and the like). These illuminated button assemblies allow a user to select responses to menu prompts in a quick and efficient manner, using a minimal user interface. However, illuminated button assemblies require careful design and meticulous construction in order to enable the user of the illuminated button assembly to be able to view the button assembly. Often, misalignment between the button and the illumination source prevents the button assembly from becoming properly illuminated. Additionally, some illuminated button assemblies overheat due to the illumination source being integrated directly into the button assembly. This causes the illumination source to burn out prematurely and thus require replacement.
Other prior art switch activating mechanisms include captive, touch-type activators, optical interrupted beam type actuators and piezo-electric-type activators. As a general rule, these latter types of devices have limited applicability and are appropriate for only certain specialized applications.
Therefore, there is a need in the art for an illuminated button assembly providing good illumination characteristics and simplicity of assembly, in relation to other button assemblies. Furthermore, such illuminated button assemblies should be able to be used without thermal radiation to the tactile portion of the button assembly.
The disadvantages associated with the prior art are overcome by the present invention of a button spring assembly with an integrated light pipe. Specifically, the button with the integrated light pipe of the present invention comprises a light pipe having an alignment key, a switch activator and at least one graphic designator molded within the light pipe itself. The light pipe fits into a button spring support assembly which is comprised of a spring molded in between and to a bottom support ring and button cap on top. The light pipe slides in through the bottom support ring into the top button cap until it reaches an alignment key located on the cap. The alignment key of the light pipe helps to align the light pipe to its correct orientation with respect to the cap and the rest of the assembly. The top button cap is a circular cap on which is molded two alignment tabs for aligning the light pipe. The bottom support ring consists of a ring with an aperture and a set of alignment notches disposed about the outside perimeter of the support ring. At least one alignment pin is also disposed in the bottom face of the lower support ring. The alignment notches and alignment pin help to align the assembly when it is being installed on a PC board in a shuttle knob mechanism.